Swages are used to expand downhole diameter of tubulars. They can be fixed conical shapes or they can be adjusted to change diameter downhole. The swages that can change diameter can be more versatile in that they can do expansion of a given tubular in stages to avoid overstressing. They can be collapsed after the expansion is complete to facilitate removal.
There are concerns when using adjustable swages that involve a plurality of segments that do the expansion. Gaps between the segments can cause lines of stress concentration that can ultimately create a fracture longitudinally. An adjustable swage design is disclosed in U.S. Publication Number 2003/01558118 A1 that involves wedge shaped segments that translate with respect to each other. Alternating wedges are held fixed while the movable segments are powered by a hydraulic piston. Applied pressure moves the movable segments into alignment with the stationary segments so that their high spots align to create the swaging diameter. The segments are dovetailed on an incline so that as they move relatively into alignment they also move radially into a larger radius. A ratchet system is incorporated to hold the position of the segments attained in response to applied hydraulic pressure to the piston. The discussion below of the basic components of this adjustable swage gives the general starting point for the present invention.
Additional flexibility can be achieved by using flexible swage 138. FIG. 1 shows it in perspective and FIGS. 2a-2c show how it is installed above a fixed swage 134. The adjustable swage 138 comprises a series of alternating upper segments 140 and lower segments 142. The segments 140 and 142 are mounted for relative, preferably slidable, movement. Each segment, 140 for example, is dovetailed into an adjacent segment 142 on both sides. The dovetailing can have a variety of shapes in cross-section; however an L shape is preferred with one side having a protruding L shape and the opposite side of that segment having a recessed L shape so that all the segments 140 and 142 can form the requisite swage structure for 360 degrees around mandrel 144. The opening 148 made by the segments 140 and 142 (see FIG. 1) fits around mandrel 144.
Segments 140 have a wide top 150 tapering down to a narrow bottom 152 with a high area 154, in between. Similarly, the oppositely oriented segments 142 have a wide bottom 156 tapering up to a narrow top 158 with a high area 160, in between. The high areas 154 and 160 are preferably identical so that they can be placed in alignment, as shown in FIG. 3a. The high areas 154 and 160 can also be lines instead of bands. If band areas are used they can be aligned or askew from the longitudinal axis. The band area surfaces can be flat, rounded, elliptical or other shapes when viewed in section. The preferred embodiment uses band areas aligned with the longitudinal axis and slightly curved. The surfaces leading to and away from the high area, such as 162 and 164 for example can be in a single or multiple inclined planes with respect to the longitudinal axis.
Segments 140 have a preferably T shaped member 166 engaged to ring 168. Ring 168 is connected to mandrel 144 at thread 170. During run in a shear pin 172 holds ring 168 to mandrel 144. Lower segments 142 are retained by T shaped members 174 to ring 176. Ring 176 is biased upwardly by piston 178. The biasing can be done in a variety of ways with a stack of Belleville washers 180 illustrated as one example. Piston 178 has seals 182 and 184 to allow pressure through opening 186 in the mandrel 144 to move up the piston 178 and pre-compress the washers 180. A lock ring 188 has teeth 190 to engage teeth 192 on the fixed swage 134, when the piston 178 is driven up. Thread 194 connects fixed swage 134 to mandrel 144. Opening 186 leads to cavity 196 for driving up piston 178. Preferably, high areas 154 and 160 do not extend out as far as the high area 198 of fixed swage 134 during the run in position shown in FIG. 2. The fixed swage 134 can have the variation in outer surface configuration previously described for the segments 140 and 142.
The operation of the method using the flexible swage 138 will now be described. The swage 134 makes contact with an obstruction. At first, an attempt to set down weight could be tried to see if swage 134 could go through the damaged portion of the casing. If this fails to work, pressure is applied from the surface. If the fixed swage 134 goes through the obstruction, the flexible swage could then land on the obstruction and then be expanded and driven through it. Pressure from the surface enters opening 186 and forces piston 178 to compress washers 180, as shown in FIG. 3b. Lower segments 142 rise in tandem with piston 178 and ring 176 until no further uphole movement is possible. This can be defined by the contact of the segments 140 and 142 with the casing or tubular 133. This contact may occur at full extension illustrated in FIG. 3b or 4, or it may occur short of attaining that position. The full extension position is defined by alignment of high areas 154 and 160. Washers 180 apply a bias to the lower segments 142 in an upward direction and that bias is locked in by lock ring 188 as teeth 190 and 192 engage as a result of movement of piston 178. At this point, downward stroking from the force magnification tool 66 forces the swage downwardly. The friction force acting on lower segments 142 augments the bias of washers 180 as the flexible swage 138 is driven down. This tends to keep the flexible swage at its maximum diameter for 360 degree swaging of the casing or tubular 133. The upper segments do not affect the load on the washers 180 when moving the flexible swage 138 up or down in the well, in the position shown in FIG. 3a. 
What the above description from the original disclosure didn't go into much detail about is what happens when segments 140 and 142 are in alignment and encounter an obstruction through which the fixed cone 134 has already cleared. Two things can happen. If the adjustable swage is to clear the obstruction, it needs to get smaller in diameter by moving from the FIG. 3a position back to the FIG. 2a position. Since segments 142 are required to move down to do this, there clearly needs to be a radial reaction force to urge the separation of the segments 140 and 142 to go to a smaller diameter through a resulting longitudinal relative movement. However the radial force must be large enough to create a longitudinal component greater than the reaction force resulting from pushing the adjustable swage against the obstruction. In other words, as shown in FIG. 3a, the aligned segments 140 and 142 are up against the tubular 10. Arrow 12 represents the pushing force from the surface that is generally coming from a set anchor and a hydraulic stroker (not shown). Other ways to create the pushing force can be used. Since the angle of surface 14 is very steep the radial component of any reaction force 16 is also very small, compared to the vertical reaction force 18 which is equal to the pushing from the surface 12, as illustrated in FIG. 3a. It is the radial force 16 that is necessary to get the diameter of the adjustable swage smaller so that it can pass the obstruction in the tubular 10. This radial component force is what drives the wedges 140 and 142 from the FIG. 4 position to the FIG. 1 position along their sloping tongue and groove edge connections. In essence the segments 142 push the fixed swage 134 downhole for the adjustable swage to reduce in diameter by assuming the FIG. 2a position. If the radial component is not sufficient to overcome the resistance to relative movement of the segments 140 and 142 under the loading imposed from being stuck against the tubular 10 the assembly will simply stall and not get through the obstruction.
What the present invention attempts to do is to enhance the radial force that urges collapse of the adjustable swage when it gets stuck on an obstruction that the fixed swage 134 has already passed. The invention seeks to redirect the longitudinal loading force to create an additional radial component when the adjustable swage is stuck. One way this is accomplished is to alter the loading angles on the mounts for the segments so as to create additional radial load component when the adjustable swage sticks in the tubular on an obstruction. Those skilled in the art will better appreciate the full scope of the invention from the claims below. The detailed description and drawings illustrate the concept of the invention by showing the preferred embodiment.